The air-conditioner generally refers herein to a room air conditioner, and specifically is a set for providing conditioned air into a room (or an enclosed space or area). Most of conventional air-conditioners perform cooling or heating in the room in convective heat-transfer manner. Specifically, a fan coil may serve as the terminal unit of an air-conditioner. A fan is provided in the fan coil in advance. Air in the region of the fan coil is circulated continuously under the action of the fan. The air is cooled or heated after flowing through a refrigerant coil or a hot-water (or chilled-water) coil, thereby cooling or heating the room. Because cooling or heating is achieved in the convective heat-transfer manner, the indoor temperature is not uniform. Either cooling or heating, the indoor temperature difference is generally greater than 10 degrees centigrade, even more than 20 degrees centigrade. Part of the cool or hot airflow is too large, which results in uncomfortableness of a human body, local cold, or even illness.
In order to solve the above problem, a radiation coil is adopted at the terminal of air-conditioner. The radiation coil is provided therein with chilled water (or hot water), and is arranged on the surface structure of the building (the ceiling surface or the ground surface). The chilled water (or hot water) in the radiation coil cools or heats a particular area in radiating manner. Such a structure of air-conditioner achieves the uniform cooling or heating to a certain extent, however, the water circulation loop of the radiation coil is required to exchange heat with a heat exchanger in a refrigerant loop of an air-conditioner firstly, and then exchange heat with the indoor air, thereby adding an intermediate heat exchange procedure and increasing the energy consumption of a power apparatus for delivering water circulation, for example, a circulating pump. Thus, the efficiency of heat exchange is low, and the installation of the system is complex.
In conclusion, it is desirable for the person skilled in the art to improve the efficiency of heat exchange.